Quarantine specs in air-gapped and slow network scenarios

What does this MR do?

Quarantine specs that consistently fail in Nightly pipelines while investigation is ongoing.

• browser_ui/4_verify/runner/register_group_runner_spec.rb fails in airgapped scenario, it might need update to support this scenario #390184 (comment 1363918338)
• browser_ui/3_create/web_ide_new/add_new_directory_in_web_ide_spec.rb - fails in slow-network scenarios, needs investigation #387609 (comment 1381078610)

E2E Test Failure issue(s)

• Failure in browser_ui/3_create/web_ide_new/add_... (#387609 - closed)
• Failure in browser_ui/4_verify/runner/register_... (#390184 - closed)

Check-list

• General code guidelines check-list
  • Code review guidelines
  • Style guides
• Quarantine test check-list
  • Follow the Quarantining Tests guide.
  • Confirm the test has a quarantine: tag with the specified quarantine type.
  • Note if the test should be quarantined for a specific environment.
  • (Optionally) In case of an emergency (e.g. blocked deployments), consider adding labels to pick into auto-deploy (Pick into auto-deploy priority1 severity1).
• Dequarantine test check-list
  • Follow the Dequarantining Tests guide.
  • Confirm the test consistently passes on the target GitLab environment(s).
• To ensure a faster turnaround, ask in the #quality_maintainers Slack channel for someone to review and merge the merge request, rather than assigning it directly.